In Ingham, north of Townsville, the Herbert River peaked at midday at 12 metres after more than 200 millimetres of rain in the past 24 hours.

The town remains cut in half, but the road from Townsville to Ingham is open.

Water is also lapping at the doors of homes and businesses at nearby Halifax and Mayor Rodger Bow says Halifax and Lucinda are cut off.

Floodwaters could isolate the town of Agnes Water in central Queensland.

The road from Agnes Water to Gladstone is likely to be closed and the route south to Bundaberg is also flooding in sections.

The Bruce Highway just south of Rockhampton is closed and the Capricorn Highway to the west is cut.

Regional director of Emergency Management Queensland Wayne Heppell says authorities have also been involved in several swift water rescues where motorists have driven into floodwaters or have been trapped by rising water.

Vinord Anand from the Tropical Cyclone Warning Centre says there is a danger the cyclone could reform as it moves towards the south-east in the coming days.

"If it moves over the water there is a chance it could develop into a tropical cyclone," he said.

The State Emergency Service received more than 130 calls for help today, mostly from communities around Mackay and Rockhampton.

Dozens of calls related to flash flooding which was threatening to or had already inundated homes and businesses.

Communities from Townsville to Bundaberg have been warned that up to 600 millimetres of rain could fall over the next couple of days.

Forecaster Tony Auden says the system may strengthen.

"It is a fairly uncertain situation and I would encourage people to keep on top of forecasts over the next few days right through eastern Queensland," Mr Auden said.

"Possibly going to be making a bit of a havoc down our way, but we're just saying residents in that area, it is possible they could become isolated as they have in the past, so just to be ready for that," he said.

"Whether it means to be out of town at the time you need to sort of pack up and start getting yourselves organised now.

"No need to panic, just if people are worried about being isolated then perhaps they might need to make themselves move onto another area."